Functionalized polyesters based on valerolactones and [12]aneN3 as effective non-viral gene vectors in HepG2 cells

Abstract

Polymer vectors hold great promise for application in gene therapy. However, some challenges such as low transfection efficiency, high toxicity, and insufficient cell selectivity still need to be addressed. Here, we proposed a simple and efficient approach to synthesize polyester vectors via ring-opening polymerization (ROP) process. Three distinct block copolymers, TMN-1/2/3, were prepared by using valerolactones with alkyl sulfide chains (6, 8, 10 carbon side chains, respectively) and propargyl valerolactone as monomers, BODIPY derivatives as fluorescent units and polymerization initiator, and further modification through click reaction with 3-azidopropyl-[12]aneN3 as positive units. Three block copolymers integrate multiple functionalities, including imaging capability, degradability, and the DNA condensation ability. Their DNA binding ability and gene transfection efficiency were systematically studied and showed good structure-activity relationship. Among them, TMN-3 with 10 carbon alkyl sulfide chain was the most effective in DNA binding ability and gene transfection efficiency, which was 18.9 times higher than that of 25 kDa PEI in HepG2 cell lines. The efficient cellular uptake, lysosomal escape, and nuclear entery of the TMN-3-DOPE/pDNA polyplexes resulted in its excellent performance. Moreover, it demonstrated that TMN-3-DOPE/pDNA exhibited significant anticancer effects upon internalization into HepG2 cells. The results indicated that TMN-3 is potential to serve as effective non-viral gene vector for tumor treatment.